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[英]Ignoring not set primitive type while converting an object to json using jackson
[英]What is correct type reference for converting the json into java object using jackson
我有以下从api获得的json输出,
{"HYR":"[{\"LastUpdatedBy\":\"Bug 101510: VMukkanagoudar\",\"IATACountryCode\":\"US\",\"MetroCodeBool\":false,\"AirportName\":\"Sawyer County\",\"Latitude\":46,\"CityName\":\"Hayward\",\"MajorAirportBool\":false,\"Longitude\":-91,\"StatusCode\":\"A\",\"DisplayNameLocal\":\"Hayward, WI (HYR-Sawyer County)\",\"DisplayNameInternational\":\"Hayward, WI, United States (HYR-Sawyer County)\",\"UpdateDate\":\"2009-03-06 20:44:00.0\",\"AirportCode\":\"HYR\",\"AirportID\":5396808,\"RegionName\":\"Wisconsin\",\"IdenticalMetroCodeBool\":false,\"ExternalName\":\"HYR\",\"CountryCode\":\"USA\"}]",
"VAA":"[{\"LastUpdatedBy\":\"fmoneo\",\"IATACountryCode\":\"FI\",\"MetroCodeBool\":false,\"AirportName\":\" \",\"Latitude\":63,\"CityName\":\"Vaasa\",\"MajorAirportBool\":true,\"Longitude\":22,\"StatusCode\":\"A\",\"DisplayNameLocal\":\"Vaasa (VAA)\",\"DisplayNameInternational\":\"Vaasa, Finland (VAA)\",\"UpdateDate\":\"2008-08-12 17:26:00.0\",\"AirportCode\":\"VAA\",\"AirportID\":4276566,\"RegionName\":\" \",\"IdenticalMetroCodeBool\":false,\"ExternalName\":\"VAA\",\"CountryCode\":\"FIN\"}]"
....(and so on)}
java对象如下
@JsonIgnoreProperties(ignoreUnknown = true)
public class Config {
@JsonProperty("AirportCode")
String airportCode;
@JsonProperty("AirportID")
Integer airportId;
@JsonProperty("MetroCodeBool")
Boolean metroCodeBool;
@JsonProperty("MajorAirportBool")
Boolean majorAirportBool;
@JsonProperty("IdenticalMetroCodeBool")
Boolean identicalMetroCodeBool;
@JsonProperty("StatusCode")
Character statusCode;
//Getters and setters
}
转换的代码是
String jsonStr = apiCall();
if(jsonStr != null)
{
ObjectMapper mapper = new ObjectMapper();
TypeReference<HashMap<String, ArrayList<Config>>> typeRef = new TypeReference<HashMap<String, ArrayList<Config>>>() {};
HashMap<String, ArrayList<AirConfig>> configMap = mapper.readValue(jsonStr, typeRef);
}
但是,我得到的错误是
com.fasterxml.jackson.databind.JsonMappingException: Can not deserialize instance of java.util.ArrayList out of VALUE_STRING token
at [Source: java.io.StringReader@2b82d59e; line: 1, column: 2] (through reference chain: java.util.HashMap["HYR"])
我相信我创建的TypeReference不正确。 任何有关如何更改它的解决方案。
在您的情况下,此JSON无效。 看部分
{"HYR":"[{\\"LastUpdatedBy\\":\\"Bug 101510:
有一种"
不应该在那里,所以有效的部分是这样的:
{"HYR":[{\\"LastUpdatedBy\\":\\"Bug 101510:
在您的情况下,您需要将HYR
的值设置为数组,但该值必须为String
值(由于引用)。 删除引号确实会产生有效的JSON数组。
数组"[
]"
开头和结尾处的json中有额外的"
。您需要删除它们。
try {
String jsonStr = "{\"HYR\":[{\"LastUpdatedBy\":\"Bug 101510: VMukkanagoudar\",\"IATACountryCode\":\"US\",\"MetroCodeBool\":false,\"AirportName\":\"Sawyer County\",\"Latitude\":46,\"CityName\":\"Hayward\",\"MajorAirportBool\":false,\"Longitude\":-91,\"StatusCode\":\"A\",\"DisplayNameLocal\":\"Hayward, WI (HYR-Sawyer County)\",\"DisplayNameInternational\":\"Hayward, WI, United States (HYR-Sawyer County)\",\"UpdateDate\":\"2009-03-06 20:44:00.0\",\"AirportCode\":\"HYR\",\"AirportID\":5396808,\"RegionName\":\"Wisconsin\",\"IdenticalMetroCodeBool\":false,\"ExternalName\":\"HYR\",\"CountryCode\":\"USA\"}]}";
if (jsonStr != null) {
ObjectMapper mapper = new ObjectMapper();
TypeReference<HashMap<String, ArrayList<Config>>> typeRef = new TypeReference<HashMap<String, ArrayList<Config>>>() {};
HashMap<String, ArrayList<Config>> configMap = mapper.readValue(jsonStr, typeRef);
ArrayList<Config> configList = configMap.get("HYR");
}
} catch (IOException e) {
e.printStackTrace();
}
}
使用(与您的Config
一起使用适当的toString
):
public static void main(String[] args) throws IOException {
String jsonStr = "{\"HYR\":\"[{\\\"LastUpdatedBy\\\":\\\"Bug 101510: VMukkanagoudar\\\",\\\"IATACountryCode\\\":\\\"US\\\",\\\"MetroCodeBool\\\":false,\\\"AirportName\\\":\\\"Sawyer County\\\",\\\"Latitude\\\":46,\\\"CityName\\\":\\\"Hayward\\\",\\\"MajorAirportBool\\\":false,\\\"Longitude\\\":-91,\\\"StatusCode\\\":\\\"A\\\",\\\"DisplayNameLocal\\\":\\\"Hayward, WI (HYR-Sawyer County)\\\",\\\"DisplayNameInternational\\\":\\\"Hayward, WI, United States (HYR-Sawyer County)\\\",\\\"UpdateDate\\\":\\\"2009-03-06 20:44:00.0\\\",\\\"AirportCode\\\":\\\"HYR\\\",\\\"AirportID\\\":5396808,\\\"RegionName\\\":\\\"Wisconsin\\\",\\\"IdenticalMetroCodeBool\\\":false,\\\"ExternalName\\\":\\\"HYR\\\",\\\"CountryCode\\\":\\\"USA\\\"}]\"}";
ObjectMapper mapper = new ObjectMapper();
// step one: deserialize the map
HashMap<String, String> configMap = mapper.readValue(jsonStr, new TypeReference<HashMap<String, String>>() {});
// step two, deserialize the value for HYR
final String hyr = configMap.get("HYR");
List<Config> configs = mapper.readValue(hyr, new TypeReference<List<Config>>() {});
System.out.println(configs);
}
在这里工作(杰克逊2.3.2)并输出:
[Foo.Config(airportCode=HYR, airportId=5396808, metroCodeBool=false, majorAirportBool=false, identicalMetroCodeBool=false, statusCode=A)]
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